Re: data specs



Sawada999 wrote:
I'm reading specs written by an engineer defining data to be transmitted. I could ask him but prefer not to show the extent of my ignorance.

The definition looks like this:

op code payload
-------------------------------
0x83 Minutes Up [31:24]
Minutes Up [23:16]
Minutes Up [15:8]
Minutes Up [7:0]
Messages Sent [31:24]
Messages Sent [23:16]
Messages Sent [15:8]
Messages Sent [7:0]

0x83 seems obvious(hex 83) but what does the rest mean?

The way I read it is that the op code is 0x83. Then the
first byte of the payload is bits 31 through 24 of the
Minutes Up value, the next byte is bits 23 through 16 of
the same value, etc. If the value Minutes Up is a 32-bit
value, then this is the same thing as saying that you send
the high-order byte, then the next-highest, then the
second-lowest, and finally the low-order byte.

I forget exactly where I last saw this, but I think this
sort of notation may be used when describing lines of a data
bus. Either that or a register. Or maybe both.

- Logan
.